Use
You can use this
BRCONNECT function to update the statistics on the Oracle database for the cost-based optimizer.By running update statistics regularly, you make sure that the database statistics are up-to-date, so improving database performance. The Oracle cost-based optimizer (CBO) uses the statistics to optimize access paths when retrieving data for queries. If the statistics are out-of-date, the CBO might generate inappropriate access paths (such as using the wrong index), resulting in poor performance.
From Release 4.0, the CBO is a standard part of the SAP System. If statistics are available for a table, the database system uses the cost-based optimizer. Otherwise, it uses the rule-based optimizer.
BRCONNECT supports update statistics for the following:
We strongly recommend you to use this BRCONNECT function rather than the equivalent SAPDBA functionality:
The reason is that we will in future no longer develop the SAPDBA functions, whereas BRCONNECT functions will always be fully up-to-date.
Integration
You can update statistics using one of the following methods:
For more information, see
We recommend you to use this approach because you can easily schedule update statistics to run automatically at specified intervals (for example, weekly).
Prerequisite
To use the CBO, make sure that the parameter
OPTIMIZER_MODE in the Oracle initialization profile init<DBSID>.ora is set to CHOOSE.Features
BRCONNECT performs update statistics using a two-step approach.
BRCONNECT:
For more information about how update statistics works, see
Internal Rules for Update Statistics.Activities
You can influence how update statistics works by using the
-force options. For more information, see -f stats.Unless you have special requirements, we recommend you to perform the standard update statistics, using one of the following tools to schedule it on a regular basis (for example, weekly):
This is also adequate after an upgrade of the database or SAP System. It runs using the OPS$ user without operator intervention.
The following are also standard commands that you can use to update statistics:
brconnect -u / -c -f stats -t missing
brconnect -u / -c -f stats -t dbstatc_tab
Example
For examples of how you can override the
internal rules for update statistics, see -force with Update Statistics.